Casing

ABSTRACT

A casing for a portable communication device having an operating face comprising a fragile input region providing recesses for operation of respective user input elements and a protection arrangement protruding beyond the fragile input region having an external profile that provides a plurality of contact points defining a contact plane such that when placed face downwards on a generally planar surface, the fragile region is spaced therefrom and impulses received on contact between the generally planar surface and the operating face are substantially dissipated away fom the fragile region.

[0001] The invention relates to personal communications devices andhousings for such devices.

[0002] Over recent years, personal communications devices ranging frommobile phones to electronic diaries and beyond have moved from beingelite items to everyday tools. In all these years, however, the designcriteria for the casing for the pieces of equipment have not reallychanged.

[0003] Communications devices of this type have casings designed withease of assembly, durability, and cost, amongst other things in mind.From the first, casings have typically been formed from moulded parts asthese lend themselves particularly to automated manufacture and can beeasily automatically clipped together for assembly. The plasticmaterials used are also relatively flexible and consequently resilientagainst the knocks and drops that will inevitably be encountered by ahighly utilised personal portable device. The design criteria have ledto similar types of casing being used for all such devices.

[0004] In accordance with an aspect of the present invention there isprovided a casing for a portable communication device having anoperating face comprising a fragile input region providing recesses foroperation of respective user input elements and a protection arrangementprotruding beyond the fragile input region having an external profilethat provides a plurality of contact points defining a contact planesuch that when placed face downwards on a generally planar surface, thefragile region is spaced therefrom and impulses received on contactbetween the generally planar surface and the face are substantiallydissipated away from the fragile region.

[0005] The present invention allows the design criteria for the casingof a handheld device to be relaxed and, in particular, differentmaterials to be used. When constrained by conventional thinking, thecasing is made from conventional materials. These are generally robustmaterials in order not to be sensitive to knocks and other impulses. Theinvention allows more fragile materials to be used. The term fragile, inthe context of this application is intended to include materials thatare less robust and that perhaps are brittle or liable to damage, inparticular shattering, if dropped.

[0006] The casing may be a conventional one part casing or a clam shell,or other two or more part arrangement, where the user input elements orkeys may be located on a different face to a display. In such two partarrangements generally respective casing portions are fixed such thatone is movable relative to the other. The movement may be rotational orlateral.

[0007] As stated above, the invention allows the opportunity for morebrittle materials to provide a face of the casing. When the surfacelayer is brittle or easily catastrophically damaged, the manner in whichthe different elements interplay is important. It may seem strange toselect a material that has brittleness as a characteristic for a durableitem but by allowing relatively brittle materials to provide a surfacelayer of such a device, materials including precious stones such assapphire or diamond could be used. These have aesthetic as well asfunctional advantages. Less costly options could also include materialssuch as glass or one of the huge number of ceramic materials that areavailable. Opening up the field from which materials of the casing andin particular the front surface can be selected allows many new designchoices to be made.

[0008] By providing protection arrangements according to aspects of theinvention, areas of the casing can be protected making it possible toutilise the unconventional materials mentioned above, and others, indesigning casings for portable communications devices. This is achievedby directing the forces resulting from impacts through more robustregions of the phone, consequently protecting those more vulnerableareas. This may be achieved by providing the protection arrangement tochannel forces into more robust elements of the casing such as a plasticframe or core.

[0009] The protection arrangement may be provided by a bezel or othercomponent surrounding the fragile region which may be a brittle surfacelayer which may be supported by a substrate. The bezel may be connectedto the substrate so as not to transfer impulses to the brittle surfacelayer. By separating the fragile region from the protection arrangementunwanted impulses are more easily prevented from transferring from thecontact points to the fragile region. A suitable structure for mountinga fragile region in a housing is described in greater detail inco-pending application GB 0031790.9. A copy is filed with thisapplication. The contact points may be provided by individual elementsprotruding beyond the fragile region and/or beyond the bezel thatprovide the additional function of connecting the bezel to the body ofthe phone. The contact points may be disposed around the periphery ofthe operating face and may include a projection on the chin of thecasing and/or raised portion proximate the earpiece.

[0010] In prior art key guards or covers the critical factor underconsideration for operation of key protection is whether or not the keyis actuated. The slide, the flip and the keyguard all provide a solutionto the same problem. By providing an electronic key guard, anyinadvertent key actuations are in effect ignored by the handset. Byproviding a cover the key actuations are ostensibly prevented. Theefficacy of such solutions depends to a greater or lesser extent on theproperties of the materials from which the covers are fabricated.

[0011] None of these solutions provide a solution that protects thephysical interaction between the mechanism of the key and the operatingface allowing more design options to be available. With increasedminiaturisation on phones the design requirements for key arrays areever more stringent, and the difficulties in providing reproduciblyactuable keys more pronounced.

[0012] One way in which problems of this type may be ameliorated isthrough the use of distinct keys. That is keys which are physically andfunctionally separate from the other keys, such that the operation ofthe one key cannot affect the operation of any other key. For such keysit is preferably that each key has a separate switching element andseparate coupling means, such as a shaft guided by two spaced apartbearings. For key mechanisms of the type described above see theapplicants co-pending application no GB 0031798.2.

[0013] For such key arrangements, the shafts and bearings are unusuallyvulnerable to sharp impulses such as those that may occur if the keyspresses quickly and with force as it may be if dropped, particularly ifthe handset is dropped face downward on a hard surface. Protruding keyswould then be depressed and may result in a sharp impulse being passedto both the shaft and the bearing. An electronic key guard would notprotect against this type of impact. Key covers have not been designedwith the physical protection of the keys in mind and may not always bepractical or desirable. The present invention provides an alternativesolution to this newly realised problem.

[0014] In an embodiment of the invention the casing forms part of aportable communications device having at least one key having an outerface protruding from the plane of the operating face in a rest positionand arranged to travel to a contact position located inward of the restposition. The protection arrangement defines the contact plane in thelocality of the at least one key such that when placed on a generallyflat surface, the resulting travel of the at least one key isrestricted.

[0015] The key may be a distinct key having a shaft travelling in adirection defined by outer and inner bearings. If the key comes to anabrupt stop when its underside abuts a bearing surface on the fragileregion defining the contact position, by restricting the travel of thekey when the device is dropped face downward, the potentially brittleregion is protected against shocks resulting from the drop. Without suchembodiments of the present invention, the shock of such an impact wouldbe absorbed through the bearing surface and dissipated in the fragileregion. This could potentially shatter such a casing element.

[0016] The bearing surface may be provided by a bearing located in anaperture in the fragile region of the handset. The bearing may itself bemade from a fragile material. The projection arrangement may then bespecifically arranged to direct impulses away from the bearings by, forexample, dissipating energy to more robust elements of the device.

[0017] In embodiments of the present invention the protectionarrangement comprises a pair of projections flanking a key or at eitherend of a row of keys. This provides a local contact plane in thevicinity of the key that protects against impact between the key andfragile region. If only a single travelling key is a potential risk to afragile operating face, a local contact plane may be all that isnecessary to protect the fragile surface in the vicinity of the key. Asan alternative, embodiments of the invention are equally applicable forarrays of such keys that are perhaps arranged in rows where theprojection arrangement comprises a respective pair of projectionsflanking each row of keys.

[0018] Embodiments of the invention will now be described in more detailwith reference to FIGS. 1 to 21 of the accompanying drawings of which:

[0019]FIG. 1 is a perspective view of a communication device showing oneembodiment of the invention;

[0020]FIG. 2 shows front, rear, sides and top views of the communicationdevice of FIG. 1;

[0021]FIG. 3 is a schematic representation of a communication devicesuitable for embodiments of the present invention;

[0022]FIG. 4 is an exploded view of the face of a communication deviceof one embodiment of the invention without keys;

[0023]FIG. 5 is a view of one layer of a light guide;

[0024]FIGS. 6a and 6 b are sections through the communication device ofFIG. 1 in the display region;

[0025]FIG. 7 is a perspective view of a side frame element and locatedrails for constructing a casing

[0026]FIG. 8 is a perspective view of the rear of the device with thebattery cover removed;

[0027]FIGS. 9a and 9 b are sections through the communication device ofFIG. 1 in the battery region;

[0028]FIG. 10 is a perspective view of the rear of the device with thebattery cover in place;

[0029]FIGS. 11a and 11 b are sections showing other embodiments of theinvention;

[0030]FIG. 12 is a perspective view of part of the input region of thedevice illustrating the location of legends associated with keys;

[0031]FIG. 13 a longitudinal section through the communication device;

[0032]FIG. 14 is a schematic section through the light guideillustrating the surfaces available for carrying the legends;

[0033]FIGS. 15 and 16 are perspective views of a partially constructedinput region of the device;

[0034]FIG. 17 is a perspective view of keys of the device includingtheir actuation mechanisms;

[0035]FIG. 18 illustrates some of the keys illustrated in FIG. 17, withthe key tips removed;

[0036]FIGS. 19a and 19 b are front and rear perspective views of theouter shell of a bezel respectively;

[0037]FIGS. 20a and 20 b are a graph showing force against distance fora key such as that illustrated in FIGS. 17 and 18, and a conventionalkey using a dome respectively; and

[0038]FIG. 21 is a bottom plan view of the device of FIG. 1 (with thechin face protector omitted).

[0039] The embodiment illustrated in FIG. 1 is a handheld communicationdevice 1 with a precious retainable casing 2. The casing 2 of the devicehas been designed to be customisable to individual taste with preciousmaterials. To enable individual devices to be created, the number ofexternal parts that the casing is formed from is relatively large incontrast to existing communication devices.

[0040] The casing 2 has an optically permeable front face 3 providing aseamless transition from a display region 4 to an input region 5 thatincludes a key array 6. The key array 6 includes a first group ofalphanumeric keys 7, for entering telephone numbers, writing textmessages (SMS), writing names (associated with phone numbers), etc. Eachof the twelve alphanumeric keys 7 is provided with a figure “0-9” or asign “#” or “*”, respectively. In an alpha mode each key is associatedwith a number of letters and special signs used in text editing.

[0041] The key array 6 additionally comprises two soft keys 8, 9, twocall handling keys 10, 11, two scroll keys 12, and an on/off key 13.

[0042] The functionality of the soft keys 8, 9 may depend on the stateof the communication device and position within the menu accessed usingthe scroll keys 12. The current functionality of the soft keys 8, 9 canbe shown in separate fields in the display region 4 just above therespective keys 8, 9.

[0043] The two call handling keys 10, 11 are used for establishing acall or a conference call, terminating a call or rejecting an incomingcall.

[0044] The two direction keys or scroll keys 12, in the handsetillustrated are placed centrally on the front surface of thecommunication device between the display region 4 and the group ofalphanumeric keys 7 perform a scrolling function.

[0045] The seamless face 3 is formed from an optically seamless lightguide 14 providing light to illuminate the display region 4 and keylegends 15 located on the light guide 14 and associated with individualkeys of the key array 6.

[0046] The front face 3 is overlaid with a pillow 16 providing apertures17 to channel sound from a loud speaker 18 and providing an appropriatefeel for an element of the device that will be located close to theuser's ear. The front face 3 is surrounded by a bezel 19 that can bemade from a precious metal.

[0047] This acts to protect the edges of the light guide 14 and can helpin some embodiments in securing the elements of the casing 2 together.

[0048] The keys of the key array in this particular embodiment arearranged to provide particular sensory guidance to the user. Aspects ofthe design also allow the light guide 14 to be made from a wide range ofmaterials including those that are brittle and so need to be carefullyhandled and protected from shattering.

[0049] The casing 2 is formed from the front face 3 surrounded by thebezel 19, a side frame 20 and a back cover 21. The interface between theside frame 20 and the bezel 19 and the side frame 20 and the rear cover21 are shielded by rails 22, 23 in this embodiment. The rails 22, 23hide raw edges from view and exposure to ensure that the device 1 isboth long lasting and elegant. The construction of the casing 2 enablesthe casing 2 to be opened with ease to update the engine 24 inside whendesired. The casing 2 is also designed to allow the device toaccommodate different sized and shaped engines 24, which may benecessary through its life.

[0050] Other elements of the design will be discussed in greater detailwith reference to the later drawings. By way of introduction, the devicewill be briefly discussed with reference to its functional elements.

[0051] The communication device 1, includes the key array 6, a display25, an antenna 26, an ear piece speaker 18, a polyphonic speaker 27, anda microphone 28. The communication device 1 is adapted for communicationvia a wireless telecommunication network, e.g. a wireless network.However, the communication device could also have been designed for acordless network. FIG. 3 shows schematically and functionally elementsof the communication device 1. The microphone 28 records the user'sspeech, and the analogue signals formed thereby are A/D converted by anA/D converter before the speech is encoded in an audio part 29. Theencoded speech signal is transferred to processor 30. The processor 30may support software in the phone. The processor 30 also forms theinterface to peripheral units of the apparatus. These may include aRandom Access Memory (RAM) 31 and a Flash Read Only Memory (ROM) 32, aSIM card 33, the display 25, and the key array 6, and perhaps a browserapplication 34, and a location module 35.

[0052] The browser application 34 can be used to request and receiveinformation from the Internet. The location module 35 enables theterminal 1 to determine its current position.

[0053] The processor 30 communicates with a transceiver 36, e.g. acircuit, which is adapted to send and receive messages in atelecommunication network. The telecommunications network may be a GSMnetwork, but the invention may also be applied in connection with othernetworks, such as other kinds of wireless networks and various forms ofcordless phone systems or in dual band phones accessing sets of thesesystems or networks. The audio part 29 speech-decodes the signal, whichis transferred from the processor 30 to the earpiece 18 via a D/Aconverter.

[0054] As discussed above, the front face 3 is optically permeable andacts as a light guide. The seamless light guide, passing light over thedisplay region 4 as well as providing light to illuminate the keylegends 15 reduces the number of lighting elements required toilluminate the device and provides a seamless transition from one areaof the front of the device to another. By using this technique fordelivering light and also allowing the light guide 14 to form the frontsurface of the device 1 as in the embodiment disclosed, the device isvisually striking, there being no visible transition from the displayregion 4 to the input region 5 where the key array 6 is located.

[0055] The embodiment illustrated in FIG. 1 has a light permeable frontface 3 that can be formed from sapphire or a similar precious stone. Assoon as a mineral such as sapphire is used in place of other moreflexible light permeable materials such as plastics, additional problemsare introduced associated with the characteristics of the material. Indesigning a durable device having, for example, a brittle material for afront piece 3 there are many difficulties. In one manifestation of theembodiment illustrated in FIGS. 1, 2 and 4 to 6, the light guide 14 isan optically seamless composite layer. As can be seen most clearly inFIG. 4, a plastics layer 37 that may be formed from Perspex or othertransparent and/or translucent materials runs the entire length of thefront face 3. There is a cut-out 38 for accommodating the ear piecespeaker 18 that is optimised for use close to the ear. There is anothercut-out accommodating a light pipe diffuser 39. This is located underthe pillow 16 and extends across the width of the device 1. By placingthe light pipe 39 under the pillow 16, a bright area on the front faceis avoided and the light visible in the light- guide will be diffused.LEDs 40, 41 are located at each side of the device at each end of thepipe 39. Light from the LEDs 40, 41 is channelled through the pipe 39and diffused. The light pipe 39 in this embodiment, is coated withreflective material so that light is channelled through the surface 42that runs along the top of the LCD display 25. Embodiments without thecoating provide some of the advantages. The diffused light isaccordingly channelled into and along the major axis of the light guide14 to provide substantially uniform lighting for the LCD 25.

[0056] In this way light is pumped into the light guide 14 along themajor axis from above the LCD 25. The light from the light pipe 39illuminates the display region 4 and provides lighting for the inputregion 5. As illustrated in FIG. 15, additional LEDs 43 or otherlighting elements are positioned along the edges of the Perspex layer orsheet 37 in the input region 5 to further illuminate the legends 15 forthe keys of the array 6. The surface of extending portions 78 of thePerspex layer or sheet 37 is shaped to channel light from adjacent topfiring LEDs 43 or the like towards the upper surface of the main portionof the layer or sheet 37. This assists in providing substantiallyuniform lighting for the input region. The additional LEDs 43 or thelike are shielded from view by the bezel 19 to avoid light spots beingvisible and encouraging a uniform diffuse light across the light guide.

[0057] The LCD 25 itself is bonded to the rear surface of the Perspexsheet 37 with an energy absorbing adhesive sheet 45. Using thistechnique and ensuring that there are no air gaps between the front ofthe LCD 25 and the Perspex sheet 37, provides a robust solution formounting the LCD 25. The surface of the LCD 25 that is delicate andgenerally needs a protective layer distanced from it is protected by thePerspex layer 37 adhered to one of its faces. The drivers 44 for the LCD25 can be seen in FIG. 5.

[0058] In the embodiment illustrated the Perspex layer 37 includesapertures 48 for locating individual keys and allowing the key shafts 49to travel to make contact with a printed circuit board 50 located withinthe casing 2 to register user input. An independently inventive keylayout, suitable for use with the general concept discussed, will bedescribed in greater detail below.

[0059] As can be seen most clearly from FIG. 4, the second layer of thecomposite light guide 51 is made in a number of sections 52-58. This isto allow for the choice of brittle materials to be used for the secondlayer 51. Sapphire has properties including its scratch resistance andoptical clarity that make it suitable for use in this context. Othertransparent or translucent materials such as glass or other mineralswould also be suitable. The light guide provides a suitable externalsurface to the device. Arrangements for the second layer similar tothose disclosed in concept in the illustrated embodiment are notnecessary when the materials are not brittle. Alternative arrangementswill, however, be apparent to the skilled man for accommodating brittlematerials in this context.

[0060] As mentioned above sapphire is brittle. When considering how tointroduce such a material into a casing 2 that is to be long lasting anddurable, problems arise. This is particularly the case when the device 1will inevitably be subjected to knocks and is likely to be dropped manytimes in its long existence. All brittle parts are bonded to a carrierformed from e.g. plastic or titanium in order to better absorb shock. Inthe embodiment described, the sapphire is formed in individual sections52-58 for ease of manufacture. Each of the pieces is adhered to thePerspex layer 37 using a UV curing adhesive based on hybrid acrylictechnology. In order to increase the durability of the composite lightguide 14 and strengthen it against damage, the sections 52-58 areadhered to a more flexible Perspex layer 37 leaving gaps 59 extendingacross the entire width. These gaps 59 act as hinges to allow thecomposite layer 14 to be relatively flexible along its major axis. Inthe embodiment illustrated, the layout of the key array 6 has beendesigned with this in mind. The alpha numeric keys 7 are arranged ingroups of three extending across the whole width of the second layer ofthe composite 51. The function keys or soft key 8, 9 are also arrangedin two groups of three. The soft keys 8, 9 and the top scroll key 12 afollows the line of the alpha numeric keys 7. The call handling keys 10,11 and the bottom scroll key 12 b, which is displaced from the line ofthe others, defines the lower edge of one of the elements 57 and theupper edge of another of the elements 56. This makes the second row ofkeys 10, 11, 12 b distinctive whilst still avoiding problems inmanufacture of the elements 52-58. The specific key array 6 illustratedhas other properties and advantages that will be discussed later.

[0061] Although the embodiment described is designed with a brittlematerial such as sapphire in mind, the resultant arrangement could beformed from any number of other materials including plastics thatprovide the required optical characteristics. Similarly different keyarrangements could be used without departing from individually inventiveconcepts that are disclosed.

[0062] When using a brittle material for a front face light guide 14problems are also encountered when connecting the front face 3 to therest of the casing elements. In the illustrated embodiment the edges ofthe brittle elements 52-58 are protected by the bezel 19 that sitsaround the whole of the face. The bezel 19, in this embodiment, isformed from a bezel support 60 overlaid with a 0.5 mm thick metal sheet,the bezel cover 61. The metal sheet 61 is bonded to the bezel support60, that may be formed from plastic, with an adhesive such as a two partepoxy adhesive or a two part acrylic adhesive. As the metal sheet 61 isrelatively thin this keeps the weight of the casing 2 down and alsoallows relatively precious metals such as titanium or gold to be used atrelatively lower cost. The bezel 19 could, however, be a single partand/or be formed from a single material for example titanium.

[0063] The transparent face 3 in this particular embodiment is securelyheld in place by a robust mechanism. The Perspex layer 37 to which theelements 52-58 are bonded extends beyond the area covered by theelements to provide a lip or edge 62 around the whole of the compositelight guide 14. This edge 62 is used to secure the front face 3 inposition as it is tucked under the bezel 19 that defines the perimeterof the front face and squeezed between the bezel 19 and the side frame20. This arrangement provides a direct route for impacts to bedissipated through the bezel and side frame without damaging the brittlefront surface.

[0064] As can be seen in FIG. 1, the bezel 19 is punctuated with frontface protectors 63 whose function will be described in more detaillater. These front face protectors 63, in this particular embodimentplay a role in holding the casing elements together. The protectorsprovide contact points that define a contact plane that prevents thebrittle front surface from making contact with the ground, for example,if dropped.

[0065] The front face protectors 63 have a tip part 64 that extends overthe bezel 19 and a shaft 65 that passes through the bezel 19 and intothe plastic side frame 20. The shaft 65 may be tightened onto the frame20 using a nut 95. In this case the nut stops the front face protectorsfrom falling out of the device. In one embodiment the shafts 65 arescrewed into the tips 64 at one end and into the side frame element 20at the other although other manners of connection could be employed. Theshaft 65 and tip 64 could also be one piece rather than two. The bezel19 and the Perspex layer 37 of the transparent face 2 are captured bythe front face protector 63 and side frame element 20 as can be seen inFIG. 9b. The front face protectors 63 accordingly grip the transparentface 3 securely between the side frame 20 and the bezel 19. The frontface protectors 63 are only located next to the key array 6. In order tosecure the transparent face 3 around its perimeter additional screws 66are added to draw the bezel 19 towards the side frame 20 and squeeze thetransparent face 3 in place. In one embodiment, the screws 66 threadthrough the side frame 20 and tap into the bezel support 60. Once thebezel support 60 is secured to the side frame 20 the outer shell 61 ofthe bezel 19 can be adhered to the support 60 to hide the tapped screwends 66. Alternatively the bezel 19 is stuck to the support first (asub-assembly) and this sub-assembly is then screwed to the frame.

[0066] As can be seen in the figures, although the more flexibletransparent substrate 37 is overlaid by the bezel 19 secured in positionby the front face protectors 63 and other connectors, the sapphire ismaintained spaced from the bezel 19 so that it is protected fromchipping or other damage as a result of contact. The edges of thesapphire elements do not protrude above the edge of the bezel 19 toprovide further protection for the more vulnerable edges. In thearrangement described, the transparent face 3 is gripped in positionbetween the bezel 19 and the side frame 20. The more flexible substrate37 could, however receive screws or other fasteners to located itrelative to the other frame members without damaging the more brittlesapphire layer.

[0067] As the protectors 63 are located in the bezel that is made ofmore robust material, and define the contact plane, all impulses aredirected through the protectors and are dissipated through the bezelaway from the brittle elements, in particular the front face. In thisway the brittle front face is protected. The contact plane additionallyinhibits the travel of the keys. This means that shocks introduced tothe front face by the key contacting the ruby bearing through thehandset being dropped face down for example are also channelled throughthe protectors 63 and dissipated in the more resilient bezel, bezelsupport and plastic side frame. This avoids to a large extent suchimpulse energies dissipating through the ruby bearings and fragile frontwhich may cause them to weaken or shatter.

[0068] To reduce the ingress of dirt or fluids a sealant 69 is locatedbetween the bezel 19 and the transparent face 3. One way in which thiscan be introduced is to paint a seal on the underside of the bezel 19which when dry is compressed between the transparent light guide 14 andthe bezel 19 when the bezel 19 and the side frame 20 are pulledtogether.

[0069] As can be seen in FIGS. 6 or 9, a first rail 22 is located in theinterface between the side frame element 20 and the front face 3. Therail 22 hides the discontinuity between the parts from sight andprotects vulnerable edges to enhance the durability of the device 1. Therail 22 may be a stamped metal piece ‘T’ shaped in section extendingaround the perimeter of the side frame 20. The stem of the ‘T’ 68 istrapped between the side frame member 20 and the bezel 19 as these twopieces are drawn together on assembly. The stem of the T has apertures70 that sit over corresponding projections 71 on the side frame 20member to prevent it from being withdrawn from between the two partswhen in position. The top of the T acts as a carrier plate to which anadditional extruded piece 72 is soldered or otherwise adhered to providea seamless finish. The stem could instead be formed from a plasticsmaterial.

[0070] The side frame member 20 in this particular embodiment is aplastic support 73 with an exterior cover 74. The cover 74 may again bea metal sheet or perhaps a wood veneer or another layer such as leather.The bonding agent most suitable for adhering the layer to the plasticframe member 73 will differ depending upon the materials that need to beadhered. For metal to plastic a suitable adhesive is a 2 part epoxyresin or 2 part acrylic adhesive. For metal to metal the adhesive wouldbe a reactive polyurethane film or a two part epoxy resin. Similarly theback cover 21 in this embodiment may have a plastic frame and be coveredwith for example a leather, wood or perhaps metal veneer. With theflexible veneer materials such as leather, it is preferable for thematerial to be taut on the frame. This is achieved during the veneeringprocess using conventional techniques. The back could also be formedfrom a ceramic material.

[0071] The transparent face 3 provides a seamless transition between thedisplay 4 and the input regions 5. In the display region 4, the LCD 25is located behind the transparent face 3 and in the input region 5 thekey mechanism 75 lies behind it. In one embodiment described, the keymechanism 75 can be seen through the front face 3. However, in otherembodiments the inner surface 76 of the Perspex substrate 37 may becoated with an opaque material to prevent the inside of the device beingseen. Alternative methods of obscuring the inner workings of the devicefrom view such as introducing additional opaque layers or obscuring theview in other ways will be apparent to the skilled man.

[0072] For embodiments where, for example, the key operating mechanism75 can be viewed through the front face 3, it may be desirable toobscure the PCB 50 from view.

[0073] The constructed casing 2 provides a housing for the printedcircuit board 50 holding the engine components 24, and a battery 79.When the device 1 is a radio telephone, a SIM card holder 80 is providedto accommodate a SIM card 81. For operation under some radio protocolsthis will clearly not be necessary.

[0074] Returning briefly to the front of the device, located above thedisplay region 4 is the pillow 16 so named because it designed for theuser to rest his or her ear against when making a telephone call. Thepillow 16 overlays the ear piece 18 of the device. As describedpreviously there is a cut-out in the Perspex substrate 37 of the lightguide 14 to accommodate the ear piece 18, the pillow 16, in theillustrated embodiment is adhered to the Perspex substrate 37 coveringthe ear piece 18. The pillow 16 provides suitable apertures 17 tochannel sound to the user.

[0075] The Perspex and sapphire light guide 14 is relatively cold to thetouch, the material of the pillow 16 can be chosen to be a material thatis inherently warmer to the touch and less prone to marking than atransparent shiny surface. Materials that are thought to be particularlysuitable are ceramics or wood and leather veneers. The shape of thepillow 16 obscures part of the LCD 25, providing opposing triangularsections 82, 83 that are used to indicate battery capacity and signalstrength respectively.

[0076] To complete the structure, the casing 2 has a rear cover 21 andinternal compartments 84, 85 suitable for retaining the engine 24 thebattery 79 and in this embodiment a SIM card 81. The device illustrated,in common with many other radio telephones, advantageously allows accessto the battery compartment 85 as the battery 79 may periodically needreplacement. In order for the engine 24 to be protected during thisactivity, the battery 79 is retained in a compartment providingconnectors to the engine 24. Along side the battery compartment 85 inthis embodiment is the SIM card holder 80. Under protocols where a SIMcard 81 is used to hold subscription information, the user may wish toremove the SIM card 81. For this reason it is convenient for the backcover 21 to be removable to expose both the battery 79 and the SIM card81. The battery compartment 85 and SIM card holder 80 are provided by aninternal casing element 87 that is secured to the side frame 20. Thismay be formed from plastic or one of many other suitable materials. Inone embodiment the compartments are formed from stamped metal sheetwhich may be stainless steel.

[0077] The battery contacts 90 protrude into the battery cavity 85 toprovide a simple way of connecting the battery 79 to the engine 24. Thebattery connection will typically be have a power connector 91, a ground92 and two signal connectors 93, 94.

[0078] In the embodiment illustrated, the power 91 a,b,c and ground 92a,b,c connectors are divided into three. This reduces the resistancebetween the battery 79 and the engine 24 as the leads are in parallel,it also reduces the chance of power being lost to the engine 24 as aresult of a harmonic resonance frequency of the connector being reachedas at all times there is likely to be at least part of each three partconnector completing the circuit between the engine 24 and the battery79.

[0079] The casing 2 is completed by assembling the back cover 21 to theside frame 20. In the illustrated embodiment, the back cover 21 isformed from three pieces 96, 97, 98. A first piece 96 overlays theantenna location. In this embodiment it provides an aperture 99 in whichthe polyphonic speaker 27 is located to provide for polyphonic sound.This additional speaker 27 has not been optimised for use in closeproximity to the ear as has the speaker 18 located beneath the pillow16. This allows it to be more effective as a handsfree speaker andenables a greater range of ring tones to be utilised. As the first piece96 also covers the antenna its dielectric constant is relevant.

[0080] In a device of this type where the casing 2 is to survivegenerations of engines 24, the materials from which is formed areimportant. They should be hard wearing and durable, retaining theirattributes for years longer than is currently required. For this reasonceramics have been considered for the back cover 21 for some embodimentsof the invention. With ceramics, however, despite having many desirablecharacteristics, for locations near an antenna relevant for devicescontaining such an element, the dielectric constant of the materialinterferes with the desired transmission pattern.

[0081] To provide many of their desirable characteristics without thedielectric constant becoming too high, the rear cover piece 96 can beformed from a material with a lower dielectric constant with a suitabledepth of layer deposited on it. This technique and suggested materialscould be used for other elements of the casing.

[0082] The rear casing element 96 covering the antenna is again screwedto the side frame element 20 and in the process captures the second rail23 similar in construction to the first rail 22 between the side frame20 and the back cover 21. Again the rail 23 is provided with apertures70 that are positioned over corresponding projections 71 on the sideframe 20 to more securely hold the rail 23 in position when the backcover 21 is attached.

[0083] A second rear casing element 97 covers the battery compartment 85and the SIM card holder 80. This element is releasably secured to theother casing elements using screws 99 to allow relatively easy access tothe SIM card 81 and battery 79. In a preferred embodiment a quarter turnof a screw 100 releases the cover element 97 to allow it to be removed.The same action can disconnect the battery 79 to allow the SIM card 81to be removed.

[0084] The second rear casing element 97 is attached to the side frame20 in a similar manner to that described in relation to the first rearcasing element.

[0085] The third element of the rear casing 98 covers the handsfreespeaker 27. This may be only relatively thin and formed from a preciousmaterial such as gold. It will be provided with a suitable aperture 102to channel sound from the polyphonic speaker 27 that may be used inhands free mode and for providing an audible ring tone.

[0086] In the embodiment described the front 3 and rear casing elements96, 97, 98 are secured to the side frame 20. A silicon sealant 69 orsimilar may be extruded around the inside of the back cover 21 toprevent unwanted ingress of dirt and fluid.

[0087] The skilled man will realise that the number of parts and themanner in which they are connected can be changed without departing fromthe several inventive concepts described. For example, in otherembodiments the casing may be held together using other techniques andin other ways.

[0088] As well as obscuring exposed edges, the rails 22, 23 provideadditional elements for customisation as they can be formed from avariety of different materials, in particular different types ofprecious metal for example gold or platinum. They also act to protectvulnerable edges of veneered frames from exposure to potentiallydamaging forces. In doing this unsightly edges are obscured from view.This provides quality and durability in keeping with the overall conceptof a retainable casing for a communications device. Regardless of thematerial of the veneer, this is a convenient arrangement for securingall the elements in place for a durable finish.

[0089] In an alternative embodiment illustrated in FIG. 4b, instead ofproviding rails 22, 23 to protect exposed edges, the adjacent edgesthemselves are turned inward 105, 106 and held in close proximity. Thisarrangement also provides the advantage of protection and keepsunsightly discontinuities from view.

[0090] A casing with an optically permeable front face provides newopportunities. In a particular embodiment, described with reference toFIGS. 12 and 14 legends 15 associated with the keys of the key array 6are located on both the front 37 a and rear 37 b surfaces of the Perspexlayer 37. With communications devices becoming ever more sophisticated,it is common for each key provided to have a number of differentfunctions. It is useful to be able to label visually the differentpossible functions associated with a key. For the alpha numeric keys 7in particular, each key is associated with a single digit and a group ofletters or symbols. Ideally these should be displayed clearly.Historically the keys have held the associated legends. As devices havebecome smaller this has, however, becomes more difficult, it being anespecial problem to distinguish between the different legends forrespective modes of operation as the letters and numbers are so small.In the illustrated embodiment, the legends 15 for associated keys arelocated on respective surfaces of the light guide 14, which as thedevice is tilted, move together or apart depending upon the angle fromwhich they are viewed. This provides a visual distinction between thelegends 15 on the different surfaces which can be used to distinguishbetween the modes of operation. As the front face is opticallypermeable, the legends appear to float in or above the device. Byspacing the legends along an axis perpendicular to the third dimension,the thickness of the front face, the front face is given someprominence, thus an additional dimension has been added to the normallyopaque front face.

[0091] In the embodiment illustrated the legends 15 are located on theoutermost and innermost surfaces of the Perspex layer 37 a, 37 b. Thelegends 15 appear to be floating in the light permeable layer. Themanner in which the legend 15 is located on the layer is a matter ofchoice for the skilled man. One method is to print the legend on to thesurface using an etched plate filled with ink. Another way may be byusing PVD (Physical Vapour Deposition) techniques to deposit the‘printing’ directly onto the Perspex layer. Other techniques for fixinglegends could be used including attaching labels.

[0092] In the embodiment discussed the legends 15 a 15 b are located onopposing surfaces of the Perspex layer 37 a 37 b. This enables a singleelement, the Perspex layer 37, to be printed instead of each of thesapphire or other pieces 52-58. Problems encountered with ink wearingoff when printing techniques are used are also avoided by protecting thesurfaces containing the printing with the second layer. In otherembodiments and to increase the depth of spacing of the legends andhence the separations possible when viewed at different angles it may bedesirable to place the legends on the innermost 37 a and outermostsurfaces 51 a of the composite. In order to fix the legend 15 printed onthe outer surface 51 a where it may encounter wear, a coating or otherprotective layer may be provided over the surface. This may not benecessary if PVD techniques are used to produce the legend 15 as suchtechniques produce a bond between the deposited layer and the substratethat is more hard wearing. In still other embodiments the legend 15could be provided on the underside 51 b of the sapphire elements and onthe innermost layer of the Perspex substrate 37 b. Again by avoiding theexternal surfaces of the transparent layer the problem of wear of thelegends 15 is largely avoided. The outermost legend is protected by thetop layer 51 of the composite light guide 14 and the innermost legend 15is not accessible.

[0093] In sandwiching the legends between two optically permeable layers37, 51 which of the two sandwiching layers carries the legend is largelyimmaterial. The properties of the respective materials, if indeed theyare different, and other factors can be taken into account in decidingwhich layer 37 b, 51 b actually carries the legend. With a compositeoptically permeable substrate, the more layers that are provided, themore visually distinguishable legends can be accommodated. For examplewith two composite layers there are three available planes for legends,with three layers, four planes and so on. If all the legends were placedadjacent a single key, the visual distinction may cause difficulty withlarge numbers of layers being used to distinguish functionalities. Otherembodiments could use the different planes for legends at differentlocations on the device so that one set of keys has a legend in a firstplane, a second set of keys in a second plane and so on.

[0094] To accentuate the illusion of the legends floating, or toincrease the distinction between the two layers, the thickness of theoptically permeable layer between the respective layers carrying thelegends can be increased. In the same way these features can be reducedby decreasing the thickness between the planes carrying the legends.

[0095] The ink or paint can be chosen by the skilled man to provide anumber of effects. The ink may, for example, be required to pearlesce orfluoresce, or be black, white, or one or more of a wide range ofcolours. As the legend is located on a light guide, fluorescent andpearlescent materials enhance the visibility of the legends.

[0096] Instead of techniques that add ink or other visible materials tothe surface merely etching the layers may be sufficient to make thelegends visible if the illumination is adequate.

[0097] Embodiments illustrating the location of legends associated withkeys in a light permeable face has been described with reference to theillustrated embodiments in the context of other independently inventivefeatures claimed in co-pending applications. The skilled man willrealise that many alterations to the specific features disclosed can bemade without departing from the scope of the invention.

[0098] The input region of the device will now be described in moredetail, primarily with regard to FIGS. 9 and 15 to 21.

[0099] The input region 5 comprises a key array 6, as described above.In this embodiment, the key array is made up of a plurality ofindividual keys 7-13. Each of these individual keys comprises a key tip64 and shaft 49 extending from substantially the centre of the key tip64, together with an upper bearing 103, O ring 107, circlet 108, springplate 110 and lower bearing 109 positioned respectively along the shaft49 a from the key tip 64. The spring plate 110 is supported by a springplate support 114 provided on the PCB 118. The spring plate comprises amain body, and a tongue 111 formed from a single piece of sheet metal.The tongue has been formed by stamping an inner portion of the sheet, sothat two sides and an end of the tongue are free from the remaining mainbody of the sheet. The spring plate also has a portion or portionsstamped out to provide an aperture for the key shaft 49 and spring platesupport 114. One end 113 of the spring plate comprises contacts forcontacting respective contact regions on the PCB. As will be appreciatedby a person skilled in the art, a single contact could be used for thispurpose, but the provision of two contacts provides greater reliability.The spring plate support 114 comprises three members upstanding from thePCB 118. These members may form part of a unitary structure, or may beseparate elements. The first member comprises a recess 115 dimensionedto receive one end 112 of the spring plate 110 and hold that end 112 inposition. The second member of the support 114 comprises a lip 116extending towards the first member. This lip 116 is provided to restrictthe upward movement of the other end 113 of the spring plate 110. Thethird member of the support 114 comprises a recess 117 for receiving theend of the tongue. This third member is positioned relative to thesecond member, such that the tongue of the spring plate 110 has to beflexed in order for the end of the tongue to correspond with its recess117. Optionally, the spring plate support may comprise a fourth membercomprising a lip extending towards the second member. In this case, thePCB contact regions are extended to the surface of this lip, so as tobring them closer to the spring plate contacts. Alternatively thecontact region bearing lip may be formed as part of the second memberitself, or eliminated altogether.

[0100] As mentioned above, in the present embodiment, the individualkeys are grouped in threes, their tips extending across the whole widthof the second layer of the composite 51. This facilitates manufacture ofthe brittle elements 52 to 58. The tips of the alphanumeric keys 7, softkeys 8, 9 and top scroll key 12 a are in alignment with those of theother keys in their group. In the remaining group of keys, however, thetip of the bottom scroll key 12 b is displaced from the line of the tipsof the other two keys in its group, namely the call handling keys 10,11. In any event, in each group the edges of adjacent key tipscomplement each other, and are closely spaced. This eliminates the needfor the composite 51, or other filler material, to extend between thekey tips. It also has the advantage of simplifying the overallappearance of the input region of the device to the user. Furtherproperties and advantages of the specific key array 6 will be discussedbelow.

[0101] As can be seen in particular from FIGS. 17 and 18, the springplates 110 and supports 114 of adjacent alphanumeric keys 7 arepositioned perpendicular to each other. This provides a geometricallysimple solution to the problem that the spring plates cannot bepositioned in alignment with the keys themselves. One cause of thisproblem in the embodiment illustrated is that the spring plate of eachouter key is longer than the average length of its corresponding keytip, and this extra length cannot be accommodated elsewhere. This isprimarily because the spring plate of each central key is only minimallysmaller than the average length of the corresponding key tip, and thekeys are closely abutted (there is only a gap of about 0.245 between thekeys) so that there is insufficient space to allow for the extra length.Furthermore, whilst the key shaft 49 of each key is substantiallycentral to the key tip 64, the key shaft aperture of the spring plate110 is off-centre. This exacerbates the problem for the outer keys, andeven results in the spring plate of each centre key not being able to beaccommodated in the space under its corresponding key tip.

[0102] The keys may be constructed, and the input region of the deviceassembled as follows. Upper bearings are inserted into the apertures 48of the Perspex layer of the device. Ruby bearings are preferablyselected for this purpose, for three main reasons. Firstly, ruby is veryhard wearing, and will thus be able to handle multiple operations of thekeys over a substantial period of time. Secondly, the upper bearings ofthis device are larger in diameter than the corresponding widths of thekey tips, which means that they will be visible in situations in whichthe front face of the device is transparent (e.g. second layer 51 may besapphire). Hence, advantage may be taken of the fact that a ruby is anattractive jewel, which the user will be pleased to see. Thirdly, theuse of a hard material such as ruby will provide greater accuracy of fitof the key in the device, as opposed to using a resilient material, suchas PFTE.

[0103] Lower bearings 109 are provided in a titanium plate which isfixed to the rear of the PCB 118. The inner and outer diameter of thelower bearings 109 are smaller than the upper bearings 103, but theircentres are aligned. They are also preferably made of differentmaterial—the material of the lower bearings having shock absorbingqualities such as PFTE.

[0104] The key shafts 49 are machined, to have a first portion 49 a ofappropriate thickness to pass through the inner diameter of the upperbearings 103 and a second reduced diameter portion 49 to pass throughthe inner diameter of the lower bearings 109. Shaft 49 and circlet 108may be machined from a single piece of metal, or the circlet 108 may besubsequently attached to the shaft 49. They are preferably formed ofstainless steel. Further, an O ring 107 is provided adjacent the circlet108, on the thicker diameter portion 49 a of the shaft 49, to provide awater seal. Both the circlet 108 and the O ring have an outer diametersmaller than that of the upper bearing, so that they are not visible tothe user when in situ. However, the circlet has an outer diametersufficiently larger than the inner diameter of the upper bearing, so asto prevent the key from falling out of the device.

[0105] The key tips are crafted into the desired shape from a desiredmaterial, which may be a metal such as gold, platinum, silver, orstainless steel. They may also bear precious stones. For example a keytip or tips may be diamond encrusted, or have a precious stone set init. Once a key shaft has been passed through an upper bearing, a key tipis joined to it. This may be achieved using conventional braisingtechniques.

[0106] The spring plate supports 114 are provided on the PCB 118. Eachspring plate support 114 is preferably of unitary structure,manufactured from lightweight metal such as aluminium. The supports maythen be soldered onto the PCB using conventional techniques. The springplate supports 114 are positioned to hold the spring plates 110 so thatthe centres of their shaft apertures align with those of the lowerbearings 109. Contact regions for the spring plate contacts are providedon the PCB (or the lip of the second or fourth member of the support asdescribed above).

[0107] The spring plates 110 themselves are provided by stamping sheetmetal, such as beryllium cooper with gold flash or the like. The plates110 are affixed to the supports 114 by positioning one end 113 of thespring plate under the lip 116 of the second member of the support 114,fitting the other end 112 of the spring plate in the recess 115 of thefirst member of the support 114, flexing the tongue so that its endcorresponds to the recess 117 of the third member of the support 114,and positioning the end of the tongue in that recess. When in position,the free end 113 of the spring plate 110 is naturally biased upwardstoward the restraining lip 116.

[0108] The dimensions of various components of the keys and theirrelative positions are important in smooth key operation. The distancebetween the upper and lower bearings has been maximised by placing themeither side of the spring plate switching mechanism and passing theshaft through the spring plate. In such a position, the bearings holdthe key straight when it is operated, thereby avoiding contact withneighbouring key tips or the need to place keys further apart to preventsuch contact. This, in turn, results in good switching functionality andfeel.

[0109] Also, the dimensions of the keys are such that the lower surfaceof each key tip 64 contacts the surface of the Perspex layer 37 beforeexcess pressure can be applied to the spring plate 110. In the presentembodiment, the circlet 108 is positioned along the shaft such that itgently rests on the spring plate when the keys are in their normalnon-depressed or rest state. Also, the thicker portion of the shaft isof an appropriate length that, when in the normal state, there is a gapbetween the lower surface of the key tips and the surface of the Perspexlayer 37 which is the same as, or only slightly greater than thedistance the circlet 108 has to travel to cause the spring platecontacts to contact the contact regions. This overcomes a potentialproblem of pressure being applied to the spring plate if the switchitself provides the end stop for the motion. The Perspex layer and inparticular the ruby bearing limit the travel of the key preventing toomuch pressure being applied to the spring plate.

[0110] The dimensions of the keys are also important for the externalappearance of the device. Preferably, the key tips are of a thicknessthat they protrude from the surface of the second layer 51 of thecomposite, at least when the keys are in the aforementioned rest state.When the composite is substantially transparent, this will give theimpression of floating keys, and add to the three dimensional effectmentioned earlier concerning the key legends 15. Furthermore, the keytips should be sufficiently deep to be partially sunk into the secondlayer of the composite, and preferably have at least two opposingsubstantially flat sides which correspond with sides of the second layerto prevent lateral rotation of the keys. A gap of the order of 0.1 mm isachieved in the present device between the keys and second layer of thecomposite: a gap insignificant to the human eye and suitable forassisting in the prevention of lateral rotation of the keys. Lateralrotation is further hindered in the present embodiment, by virtue of theprovision of mirrored slanting of the sides of adjacent keys.

[0111] In order to ensure the correct relative spacing of elements ofthe key, the Perspex layer 37, PCB 118, and titanium plate 77 areclamped together. In this embodiment, the clamping is provided by thefront face protectors 63, and by the provision of additional tappedbosses in projections 68 of the Perspex plate and associated fixingmeans. Consequently, once the keys have been positioned, the Perspexlayer, PCB and titanium plate can be clamped together using the bossesand fixing means, thereby holding the keys in place and forming amanageable module. This module may then be readily installed in thedevice using the front face protectors as described above with referenceto FIG. 9B.

[0112] Operation of the keys of the device will now be described. As theuser applies pressure to a key tip, the shaft moves downwards,travelling through the bearings and shaft aperture of the spring plate.This results in the circlet applying pressure to the part of the mainbody of the spring plate which defines the shaft aperture. Continuedpressure on the key tip will then cause the circlet to apply anincreasing force to this part of the spring plate, causing the main bodyto deform around the circlet. Eventually, this deformation will causethe tongue to overcentre, resulting in the free end 113 of the springplate 110 flicking from its naturally biased position (upwards towardsthe restraining lip 116) to a second position, in which the spring platecontacts contact the contact regions on the PCB. An electrical signal isconsequently sent to the processor indicative of actuation of that key.This arrangement gives a distinct click providing a clear qualityindication to the user that the key has been actuated. As the userremoves pressure from the key tip, the circlet, in turn, removespressure from the spring plate 110. The tongue promptly returns to itsnormal or rest position, and the free end of the spring plate flicks upto its naturally biased position, breaking the contact and returning thekey tip to its rest position.

[0113] If the user did not for some reason release the pressure, the keycould not travel indefinitely. It would eventually stop through contactbetween the underside of the key and a bearing surface. The contact inone embodiment is between the underside of the key tip and the rubybearing located in the Perspex layer. This arrangement protects theswitching mechanism from being pressured. As a result of this stoppingmechanism a sharp blow to the key tip will result in the transfer offorce at the contact point. As contact is made at the ruby bearing theenergy of the blow will be dissipated through the bearing and into thePerspex and sapphire layers causing possible damage.

[0114]FIG. 20a is a graph illustrating the force against distanceprofile for a key such as that illustrated in FIGS. 17 and 18. Thisprofile improves the tactility of the key over, for example, a typicalkeydome arrangement, which had a fairly flat profile as can be seen inFIG. 20b. When using a conventional key dome type arrangement, the userhas to apply a constant force until the point where the key actuates. Asa result, he does not get a tactile indication that he is nearing theposition when actuation is likely to occur. In contrast, when using thedevice illustrated in FIGS. 17 and 18, the user can realise the factthat he is nearing the position when actuation is likely to occur as heis having to increase the force applied for a given travel of the key.Furthermore, the user is informed when actuation takes place, and againwhen deactuation takes place, by respective clicking sounds provided bythe key.

[0115] The central V shaped key tips of the embodiment illustrated inFIG. 1 enable the user to determine the central vertical axis of thedevice both by sight and by touch. This is made even easier by thepillow 16 being provided with an apex. Consequently the user can quicklylocate a desired central key. The apexes of each central key tip alsoidentify the mid point along the length of the key tip, the point fromwhich the key shaft 49 extends. Hence, they facilitate more accuratedepression of the key. This, in turn, may assist in the prevention ofcontact with neighbouring key tips or the need to place keys furtherapart to prevent such contact.

[0116] Likewise, in this embodiment, the combination of adjacent outerkey tips and front face protectors forming a V shape enable the user todetermine the position of the vertical axes to one side of which theouter keys lie. Consequently, the user can quickly locate a desiredouter key. The key location process is facilitated in this embodiment asthe outer key tips extend to the interface between the second layer ofthe composite 51 and the bezel 19.

[0117] The front face of the device illustrated in FIG. 1 is protectedby the pillow and protectors 63. The protectors help to reduce theeffects of unexpected impacts on the front face and the key mechanisms.The front face 3 is slightly concave, with the highest points lyingalong its central longitudinal axis. Hence, ordinarily, if placed facedown, the device would rest on this axis, resulting in scratches to itssurface. Clearly, this is not acceptable, particularly when the secondlayer of composite is sapphire or the like. The device illustrated inFIG. 1 has been designed to avoid this problem. The pillow 16 and faceprotector 63 a prevent the device resting on the second layer ofcomposite. Also, as mentioned above, in the preferred embodiment the keytips protrude slightly from the surface. Hence, the central key tips toomay protect the second layer of composite from damage. However,preferably the pillow 16 and chin front face protector 63 a are raisedsufficiently above the front surface, that the device does not rest onthe central key tips either, so as to protect them from damage too.

[0118] The device is also designed so that the front face is protectedif the edge of the face is knocked. As can be seen from the plan view ofthe device, depicted in FIG. 21, the bezel front face protectors 63 bprotrude beyond the surface of the second layer of composite along theinterface with the bezel, thereby protecting the second layer ofcomposite from damage in that region. They also reduce the likelihood ofdamage to the bezel due to knocks. Moreover, they protrude further thanthe adjacent key tips, hence protecting those key tips from damage too.

[0119] One particular benefit of the protectors 63 mentioned above,especially those located on the bezel flanking each row of keys, is thatthey are dimensioned so as to prevent the keys from reaching their fullextent if the handset is accidentally, for example, dropped facedownwards. This avoids the possible damage caused if the key tripreceives a sharp blow making contact with the ruby bearing as describedearlier. The protectors could also be arranged to prevent the keys frombeing accidentally actuated if, for example, the device was placed facedown. That is, the top surface of the front face protector tips couldeither be at the same level or higher than the top surface of a key tip(e.g. as in the relationship between the protectors 63 b and theadjacent outer key tips). In this instance the keys would be untouchedor relatively unaffected by being placed or dropped face down on asurface. A protective effect can still be achieved if the protectors 63are at a lower level than the top surface of a key tip. In the case of aconvex front as is the case in some embodiments of the invention, theprotectors may be flush with some of the outermost surface of adjacentkeys while still being below the surface of more central keys. Underthese circumstances, to avoid the ruby bearing being shocked anddissipating energy in an uncontrolled fashion into the front face ifdropped, the distance between the top surface of the protector and keytips must be smaller than the distance the key needs to travel in orderto reach its contact position i.e. the position when it abuts the rubybearing. If the key protectors 63 are also going to act to reduceinadvertent actuations, the distance between the top surface of the keytip and the protector should be smaller than the distance the key needsto travel in order for the spring plate contacts to contact the PCBcontact region for actuation the key.

[0120] The bezel and key/face protectors as a whole channel impactforces through the bezel and into the plastic frame, reducing the chancethat such impulses will damage the more fragile regions of the device.

[0121] Aspects of the invention have been discussed with reference to aradio telephone function. It will be clear to the skilled man that theseaspects apply equally to other portable communications devicessupporting in addition or as an alternative other functions, such as,amongst others electronic diaries, and electronic notepads.

[0122] The present invention includes any novel feature or combinationof features disclosed herein either explicitly or any generalisationthereof irrespective of whether or not it relates to the claimedinvention or mitigates any or all of the problems addressed.

[0123] In view of the foregoing description it will be evident to aperson skilled in the art that various modifications may be made withinthe scope of the invention.

1. A casing for a portable communication device having an operating facecomprising a fragile input region providing recesses for operation ofrespective user input elements; and a protection arrangement protrudingbeyond the fragile input region having an external profile that providesa plurality of contact points defining a contact plane such that whenplaced face downwards on a generally planar surface, the fragile regionis spaced therefrom and impulses received on contact between thegenerally planar surface and the operating face are substantiallydissipated away from the fragile region.
 2. A casing according to claim1, wherein the protection arrangement forms part of a relatively robustregion.
 3. A casing according to claim 1 or claim 2, wherein the fragileinput region and the protection arrangement are provided by respectivecasing elements.
 4. A casing according to any preceding claim, whereinthe fragile input region is formed from a brittle material.
 5. A casingaccording to any preceding claim, wherein the fragile input regioncomprises a brittle surface layer
 6. A casing according to claim 5wherein the brittle surface layer is disposed on a substrate.
 7. Acasing according to any preceding claim, wherein the protectionarrangement comprises a bezel surrounding the fragile input region.
 8. Acasing according to claim 7, wherein the contact points are provided byface protectors providing the additional function of connecting thebezel to other elements of the casing.
 9. A casing according to anypreceding claim, wherein the contact points are arranged to directimpulses away from the fragile region.
 10. A casing according to anypreceding claim, wherein the contact points are disposed around theperiphery of the operating face.
 11. A casing according to any precedingclaim, wherein the projection arrangement comprises a projection on thechin of the casing.
 12. A casing according to any preceding claim,wherein the projection arrangement comprises a raised portion proximatethe earpiece.
 13. A handset comprising a casing in accordance with claim1 including at least one key having an outer face protruding from theplane of the operating face in a rest position and arranged to travel toa contact position located inward of the rest position; wherein theprotection arrangement defines the contact plane in the locality of theat least one key such that when placed operating face down on agenerally flat surface, the resulting travel of the at least one key isrestricted.
 14. A handset according to claim 13, wherein the contactposition is defined by an abutment between the inner face of the key anda bearing surface of the operating face of the handset.
 15. A handsetaccording to claim 14, wherein the bearing surface is provided by abearing located in an aperture in the front face of the handset.
 16. Ahandset according to claim 15, wherein the bearing is a ruby bearing.17. A handset according to any one of claims 13 to 16, wherein the atleast one key comprises a row of keys.
 18. A handset according to anyone of claims 13 to 17, wherein the protection arrangement comprises apair of projections flanking the at least one key.
 19. A handsetaccording to any one of claims 13 to 16, wherein the at least one keycomprises a plurality of rows of keys and the protection arrangementcomprises a respective pair of projections flanking each row of theplurality of rows of keys.
 20. A handset according to any one of claims13 to 19, wherein the at least one key is a distinct key having a shafttravelling in a direction defined by outer and inner bearings.
 21. Ahandset according to any one of claims 13 to 20, wherein the contactposition is defined by an abutment between the key and the outer bearingsurface.
 22. A handset according to any one of claims 1 to 12 at leastone key having an outer face protruding from the plane of the operatingface in a rest position and arranged to travel to a contact positionlocated inward of the rest position, the extent of travel being definedby contact between the underside of the at least one key and a bearingsurface of the operating face.
 23. A casing substantially ashereinbefore described with reference to FIGS. 1 to 21 of the drawings.24. A handheld communication device substantially as hereinbeforedescribed with reference to FIGS. 1 to 21 of the drawings.